Toward Improving QoS and Energy Efficiency in Wireless Body Area Networks

The performance of wireless body area networks (WBANs) depends mainly on the quality of service (QoS) and energy efficiency. First, the network environment of a WBAN changes rapidly due to changes in human body movements, which leads to unguaranteed service quality, delivery probability, and delay. Second, energy is limited due to the small size of the sensors. To solve these problems, in this article, we first propose an optimization method for the sampling start time of sensor nodes. We comprehensively consider sampling rate, sampling time, transmission rate and other factors and set the appropriate sampling start time for the nodes through quantitative analysis of the relationship between these factors, which greatly reduces the waiting time delay of the nodes. Furthermore, an optimization method for the data frame length is proposed, where the relationship between the optimal data frame length and the average delivery probability is given quantitatively by considering the channel model. The experimental results show that the proposed scheme, relative to the compared schemes, achieves substantial improvements in QoS and energy efficiency and has more obvious advantages when the channel conditions of the nodes are worse.